The present invention relates to a display device which utilizes an emission of electrons into a vacuum, and more particularly, to an emissive flat panel display device including a back panel which is provided with cathode electrodes having electron sources formed of nanotube and gate electrodes which control an emission quantity of electrons from the electron sources and a face panel which is provided with phosphor layers of plurality of colors which emit light upon excitation of electrons taken out from the back panel and anode electrodes.
As a display device which exhibits the high brightness and the high definition, color cathode ray tubes have been popularly used conventionally. However, along with the recent request for the higher quality of images of information processing equipment or television broadcasting, the demand for planar display devices which are light in weight and require a small space while exhibiting the high brightness and the high definition has been increasing.
As typical examples, liquid crystal display devices, plasma display devices and the like have been put into practice. Further, particularly, as display devices which can realize the higher brightness, it is expected that various kinds of panel-type display devices including an electron emission type display device which utilizes an emission of electrons from electron sources into a vacuum and an organic EL display which is characterized by low power consumption will be commercialized soon. Here, the plasma display device, the electron emission type display device or the organic EL display device which requires no auxiliary illumination light source is referred to as a self-luminous flat panel display device or an emissive flat panel display device.
Among such flat panel display devices, as the above-mentioned field emission type display device, a display device having a cone-shaped electron emission structure which was invented by C. A. Spindt et al, a display device having an electron emission structure of a metal-insulator-metal (MIM) type, a display device having an electron emission structure which utilizes an electron emission phenomenon based on a quantum theory tunneling effect (also referred to as “a surface conduction type electron source,), and a display device which utilizes an electron emission phenomenon which a diamond film, a graphite film and nanotube represented by carbon nanotubes and the like possesses have been known.
The field emission type display device which is one example of the emissive flat panel display device is constituted by sealing a back panel which forms field-emission-type electron sources and gate electrodes which constitute control electrodes on an inner surface thereof and a face panel which includes phosphor layers of a plurality of colors and an anode electrode (an anode) on an inner surface thereof which opposingly faces the back panel while interposing a sealing frame between inner peripheries of both panels and by evacuating the inside defined by the back panel, the face panel and the sealing frame. The back panel includes a plurality of cathode lines having electron sources which extend in the first direction, are arranged in parallel in the second direction which crosses the first direction and gate electrodes which extend in the second direction and are arranged in parallel in the first direction on the back substrate which is preferably made of glass, alumina or the like. Then, in response to the potential difference between the cathode electrode and the gate electrode, an emission quantity (including ON and OFF) of electrons from the electron sources is controlled.
Further, the face panel includes phosphor layers and an anode electrode on the face substrate which is formed of a light transmitting material such as glass or the like. The sealing frame is fixedly adhered to inner peripheries of the back panel and the face panel using an adhesive material such as frit glass. The degree of vacuum in the inside defined by the back panel, the face panel and the sealing frame is, for example, 10−5 to 10−7 Torr. When the field emission type display device has a large-sized display screen, both panels are fixed to each other by interposing gap holding members (spacers) between the back panel and the face panel thus holding the gap between both substrates to a given distance.
Here, as the literature which discloses a related art on the emissive flat panel display device which adopts carbon nanotubes which are a typical example of nanotubes as electron sources, many literatures are reported including “SID 99 Digest, pp. 1134–1137”.